JP5760303B2 - Heat supply system - Google Patents

Description

  The present invention relates to a heat supply system.

  As a heat supply system, a configuration is generally known in which the heat of steam generated by a boiler is transmitted to an object (see, for example, Patent Document 1). In addition, a configuration in which heat of a heat pump medium is transmitted to an object is known. It is known that a heat pump has a relatively high energy utilization efficiency by utilizing heat outside the cycle (heat of a low-temperature heat source).

JP-A-6-249450

  A system using a boiler has a relatively low primary energy efficiency. On the other hand, in a system using a heat pump, if the amount of heat and temperature supplied from a low-temperature heat source are unstable, there may be a situation where the heat demand cannot be sufficiently met.

  An object of this invention is to provide a heat supply system with high energy efficiency.

According to an aspect of the present invention, there is provided a first device that includes a supply device that supplies air toward an external device and a heat pump through which a second fluid flows, wherein the heat of the second fluid can be transferred to the air. A first device; a second device that heats the air from the first device; and a control device that controls the heat pump in a load state between a full load including a partial load state and a no-load state. The second device heats the third fluid, heat of the third fluid can be transferred to the air from the first device, and the heat pump discharges the third fluid discharged from the second device. A heat absorption part capable of absorbing heat from the air, the heat absorption part can further absorb heat from the air exhausted from the external device, and the second device is a combustion chamber for heating the air A boiler having the control device And the flow rate of the air required in the external device, based on the primary energy efficiency, the heat supply system for controlling the load ratio of the heat pump is provided.

  According to this heat supply system, the combination of the first device including the heat pump and the other second device is optimized, and as a result, the energy efficiency is improved.

It is the schematic which shows one Embodiment. It is a figure which shows an example of the mode of heat exchange of the air for drying (no feed water heating (preheating)). It is a figure which shows another example of the mode of the heat exchange of the air for drying (with water supply heating (preheating)). It is a flowchart which shows an example of operation | movement of a heat supply system. It is a figure which shows an example of the performance curve of the compressor in a heat pump. It is a figure which shows the relationship between the temperature of a low-temperature heat source, and partial load efficiency. It is the schematic which shows other embodiment.

  Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic diagram illustrating a heat supply system S1 according to an embodiment.

  As shown in FIG. 1, the heat supply system S1 includes a first heating device (first device) 12 having a heat pump (heat pump circuit) 20 and a second heating device (second device) 14 having a heating device other than the heat pump. And a supply device 16 and a control device 18. The control device 18 comprehensively controls the entire system. The configuration of the heat supply system S1 can be variously changed according to design requirements.

  In the first heating device 12, the heat pump 20 is a device that pumps heat from a low-temperature object and applies heat to the high-temperature object by a cycle including evaporation, compression, condensation, and expansion processes. A heat pump generally has the advantage of relatively high energy efficiency and, as a result, relatively low emissions of carbon dioxide and the like.

  In the present embodiment, the heat pump 20 has a heat absorption part 21, a compression part 22, a heat radiation part 23, and an expansion part 24, which are connected via a conduit. In the heat pump 20, the working fluid flows in the conduit. In the present embodiment, the heat pump 20 can heat the heated fluid (first fluid, air, etc.) flowing through the supply device 16 using the heat of the working fluid.

  In the heat absorption part 21, the working fluid flowing through the main path 25 absorbs heat from a heat source outside the cycle (low temperature heat source). In this embodiment, the heat absorption part 21 of the heat pump 20 includes an evaporator that is thermally connected to the heat radiating pipe 91 of the external device 90 and in which the working fluid evaporates. The heat of the medium (refrigerant, etc.) flowing through the heat radiating pipe 91 is absorbed by the heat absorbing part 21 of the heat pump 20. It is also possible to use the exhaust heat of the external device 90 as a heat source. The heat absorption part 21 can also be configured to absorb the heat of other heat sources such as the atmosphere. As will be described later, in the present embodiment, the heat absorbing unit 21 can absorb heat from the fluid (drain) discharged from the second heating device 14, and further, the fluid (exhaust gas) discharged from the external device 95. Can absorb heat from

  The compression unit 22 compresses the working fluid by a compressor or the like. At this time, the temperature of the working fluid usually increases. The compression unit 22 can have a single-stage compression structure or a multistage compression structure that compresses the working fluid into a plurality of stages. The number of compression stages is set according to the specification of the heat supply system S1, and is 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 or more. Among the various compressors such as an axial flow compressor, a centrifugal compressor, a reciprocating compressor, and a rotary compressor, a compressor suitable for compressing the working fluid is applied. Power is supplied to the compressor. In the compression unit 22 having a multistage compression structure, a multiaxial compression structure or a coaxial compression structure can be applied.

  The heat radiating part 23 has a conduit through which the working fluid compressed by the compressing part 22 flows, and gives heat of the working fluid flowing in the main path 25 to a heat source (heated fluid) outside the cycle. The number of heat radiation units is set according to the specification of the system S1, and is 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 or more.

  In the present embodiment, the heat radiating portion 23 includes a first heat radiating portion 23A and a second heat radiating portion 23B. The first heat radiating unit 23 </ b> A includes a conduit through which the working fluid from the compression unit 22 flows and heat from the working fluid is transmitted to the heated fluid that flows through the supply device 16. The second heat radiating portion 23B has a conduit through which the working fluid from the first heat radiating portion 23A flows and heat from the working fluid is transmitted to the fluid flowing through the second heating device 14. In the present embodiment, the heat pump 20 can have a configuration for controlling the flow rate of the working fluid flowing through the first heat radiating portion 23A and / or the second heat radiating portion 23B. In this configuration, for example, the heat pump 20 can include a bypass path, a flow sensor, a flow path control valve, and the like.

  The expansion unit 24 expands the working fluid by a pressure reducing valve, a turbine, or the like. At this time, the temperature of the working fluid usually decreases. When a turbine is used, power can be taken out from the expansion unit 24, and the power may be supplied to the compression unit 22, for example. As a working fluid used in the heat pump 20, various known heat media such as a fluorocarbon medium (HFC 245fa, R134a, etc.), ammonia, water, carbon dioxide, air, and the like are selected according to the specifications and heat balance of the system S1. Used. At least a part of the working fluid flowing through the heat radiating portion 23 of the heat pump 20 can be in a supercritical state.

  In this embodiment, the 2nd heating apparatus 14 has the boiler 40 as heating apparatuses other than a heat pump. In this embodiment, the boiler 40 burns fuels, such as oil and gas, and heats a heat medium (water etc.) with the combustion heat. Various known forms can be applied as the boiler 40. Additionally or alternatively, the second heating device 14 can have other heating devices such as an electric heater.

  In the present embodiment, the second heating device 14 heats the heat medium from the preheating unit (feed water heating unit) 142 in which the heat of the working fluid flowing through the heat pump 20 is transmitted to the heat medium (water or the like), and the preheating unit 142. Part 144. The second heating device 14 can further include a conduit through which water as a heat medium flows, a fluid drive device such as a pump, a valve for fluid control, and the like.

  The preheating unit 142 includes a conduit that is thermally connected to the second heat radiating unit 23B of the heat pump 20 in the first heating device 12 and through which water flows. The heat exchanger 31 is configured including the preheating unit 142 and the second heat radiation unit 23B. The heat exchanger 31 has a counter-current heat exchange structure in which a low-temperature fluid (water supplied to the second heating device 14 (boiler 40)) and a high-temperature fluid (working fluid in the heat pump 20) flow opposite to each other. Can have. Alternatively, the heat exchanger 31 may have a parallel flow type heat exchange structure in which a high-temperature fluid and a low-temperature fluid flow in parallel. In the present embodiment, various known heat exchange structures of the heat exchanger 31 can be employed. The conduit of the second heat radiating portion 23B and the conduit of the preheating portion 142 are disposed in contact with or adjacent to each other. For example, the conduit of the second heat radiating portion 23B can be disposed on the outer peripheral surface or inside of the conduit of the preheating portion 142. In the preheating part 142, the water in the conduit is preheated by the heat transferred from the heat radiating part 23 of the heat pump 20, and the temperature rises (feed water heating).

  The heating unit 144 further heats the preheated water from the preheating unit 142. In the present embodiment, the heating unit 144 is thermally connected to the combustion chamber 42 of the boiler 40. In other embodiments, the heating portion 144 can be thermally connected to an electric heater. In the heating unit 144, the water in the conduit evaporates into steam by the heat transferred from the combustion chamber 42 of the boiler 40.

  The supply device 16 supplies the fluid (heated fluid) heated using the first heating device 12 and the second heating device 14 to the external device 95. The supply device 16 includes a first heating unit 62 and a second heating unit 64. The supply device 16 can further include a conduit through which the fluid to be heated flows, a fluid drive device such as a pump, a valve for fluid control, and the like.

  In the present embodiment, the fluid to be heated is air, and high temperature air (drying air) is supplied to the external device 95. In other embodiments, the fluid to be heated can be air other than drying or a fluid other than air. Examples of heated fluids other than air include compressed water, chemicals, and viscous liquids.

  The first heating unit 62 includes a conduit that is thermally connected to the first heat radiating unit 23A of the heat pump 20 in the first heating device 12 and through which air flows. The heat exchanger 32 is configured including the first heating unit 62 and the first heat radiating unit 23A. The heat exchanger 32 can have a countercurrent heat exchange structure in which a low-temperature fluid (air in the supply device 16) and a high-temperature fluid (working fluid in the heat pump 20) flow opposite to each other. Alternatively, the heat exchanger 32 may have a parallel flow type heat exchange structure in which a high-temperature fluid and a low-temperature fluid flow in parallel. In the present embodiment, various known heat exchange structures of the heat exchanger 32 can be employed. The conduit of the first heat radiating part 23A and the conduit of the first heating part 62 are arranged in contact with or adjacent to each other. For example, the conduit of the first heat radiating unit 23 </ b> A can be disposed on the outer peripheral surface or inside of the conduit of the first heating unit 62. In the first heating unit 62, the temperature of the air in the conduit rises due to the heat transferred from the first heat radiating unit 23 </ b> A of the heat pump 20.

  The second heating unit 64 includes a conduit that is thermally connected to the heat dissipation unit 146 of the second heating device 14 and through which the air from the first heating unit 62 flows. The heat exchanger 33 is configured including the second heating unit 64 and the heat radiating unit 146. The heat exchanger 33 may have a countercurrent heat exchange structure in which a low-temperature fluid (air in the supply device 16) and a high-temperature fluid (steam in the heat radiation unit 146) flow opposite to each other. Alternatively, the heat exchanger 33 may have a parallel flow type heat exchange structure in which a high-temperature fluid and a low-temperature fluid flow in parallel. In the present embodiment, various known heat exchange structures of the heat exchanger 33 can be employed. The conduit of the heat radiating unit 146 and the conduit of the second heating unit 64 are disposed in contact with or adjacent to each other. For example, the conduit of the heat radiating unit 146 can be disposed on the outer peripheral surface or inside of the conduit of the second heating unit 64. In the second heating unit 64, the temperature of the air in the conduit further increases due to the heat transferred from the heat radiating unit 146 of the second heating device 14.

  In the present embodiment, the output temperature of the fluid to be heated (drying air) from the supply device 16 can be changed according to the heat demand. The output temperature can be, for example, 50, 60, 70, 80, 90, 100, 110, 120, 130, 140, 150, 160, 170, 180, 190, or 200 ° C. or higher.

  In the present embodiment, the system S1 has a first return path 70 for reusing fluid (drain) from the second heating device 14 (boiler 40) after heat output. The fluid after radiating heat from the heat radiating portion 146 flows through the first return path 70. The fluid (water) from the first return path 70 flows through the heat radiating pipe 91 and can exchange heat with the working fluid of the first heating device 12 (the heat absorbing portion 21 of the heat pump 20). The heat of the fluid from the first return path 70 is absorbed by the heat absorption part 21 of the heat pump 20. Alternatively, the fluid (water) from the return path 70 is charged again into the second heating device 14 (boiler 40). Excess fluid from the second heating device 14 can be appropriately discharged to the outside. By reusing the fluid, the operation cost can be reduced.

  In the present embodiment, the system S1 has a second return path 72 for reusing the heated fluid (exhaust gas) from the external device 95 after heat output. The fluid after radiating heat from the external device 95 flows through the second return path 72. The fluid (air) from the second return path 72 flows through the heat radiating pipe 74. The heat radiating pipe 74 of the second return path 72 is thermally connected to a conduit 93 fluidly connected to the heat radiating pipe 91 of the external device 90 on the low temperature heat source side. The heat of the fluid (air) from the second return path 72 is absorbed by the medium (refrigerant etc.) flowing through the conduit 93. The medium flows through the heat radiating pipe 91, and the heat is absorbed by the heat absorbing portion 21 of the heat pump 20. By reusing the fluid, the operation cost can be reduced.

  In the present embodiment, the system S1 includes heat demand information (required temperature, required flow rate) in the external device 95, output information (temperature, pressure, etc.) of the boiler 40, and low-temperature heat source information for the heat pump 20 (exhaust heat in the external device 90). Sensors for detecting information, etc.) as necessary. The control device 18 can comprehensively control the entire system S1 based on various information.

  In the present embodiment, the control device 18 can control the operation of the heat pump 20 in a load state between a full load including a partial load state and no load. According to the present embodiment, the control including the partial load operation of the heat pump 20 and the backup by the boiler 40 can improve the energy efficiency of the entire system S1.

  In the present embodiment, air (fluid supplied to the external device 95) as a fluid to be heated heated using the heat pump 20 can be further heated using the boiler 40. Therefore, a relatively high temperature fluid can be supplied to the external device 95, and it can flexibly respond to a relatively high level of heat demand.

Here, the following formulas (1) and (1 ′) hold from the energy conservation law in heat exchange. In the following description, A: heat transfer area [m ² ], G: mass flow rate [kg / s], h: enthalpy [J / kg / K], k: heat transmissivity [J / s / m ^2] / K], T: temperature [K], W: heat quantity [J / s]. The subscripts in each equation are: Air: air, BS: boiler steam, BFW: boiler feed water, D: demand (demand), HP: heat pump, WH: feed water heater, in: inlet, out: outlet.

Here, ΔW _BFW is an appropriate value and may be zero.

  FIG. 2 shows a state of heat exchange of the drying air when the feed water heating by the heat pump 20 (preheating in the boiler 40) is “none”. In FIG. 2, it is assumed that a supercritical working fluid flows through the heat pump 20. The same can be set in the condensation area.

If T _HP-in , T _HP-out , and T _Air-in are determined, T _Air-out can be obtained using, for example, the following equations (2) and (2 ′).

That is, the drying air is heated from the inlet temperature (atmospheric temperature) to T _Air-out by the heat pump 20, and from T _Air-out to TD is heated by steam from the boiler.

  FIG. 3 shows a state of heat exchange of the drying air when the feed water heating by the heat pump 20 (preheating in the boiler 40) is “present”. Basically, if the amount of heat supplied by the heat pump 20 is sufficient, it is considered that heating the feed water leads to an improvement in the utilization rate of the heat pump 20 and is advantageous in realizing energy saving.

If T _HP-WHin , T _BFW-out , and T _BFW-in are determined, T _HP-WHout can be obtained using, for example, the following equation (3).

When T _BFW-out is not fixed, first, the initial value of T _BFW-out is temporarily input into Equation (3), and the _{process ends when} an appropriate value of T _HP-WHout is obtained by calculation. Otherwise, recalculation is performed by replacing the initial value of _TBFW-out .

T _BFW-out is in response to the supply heat quantity of the heat pump 20, believed to be the optimum value that is energy saving in the entire system (eventually range adjustment is a _{T BFW-out,} to determine the optimal point).

  Thereafter, the heating of the drying air is calculated in the same manner as when there is no feed water heating by the heat pump 20.

  The steam flow rate can be calculated from the equation (1) as in the following equations (4) and (5).

  The flow rate and temperature of the low-temperature heat source may vary with time. Even in that case, it is necessary to reliably supply heat for drying the process.

FIG. 4 is a flowchart illustrating an example of the operation of the system S1.
As shown in FIG. 4, first, information related to heat demand (temperature and flow rate), outlet conditions (temperature and pressure) of the boiler 40, water supply conditions, and low-temperature heat source conditions (heat exhaust heat conditions, temperature and flow rate) for the heat pump 20. Are input (steps 301, 302, and 303).

  Next, based on the input information and information on the performance of the heat pump 20, the output (temperature and flow rate) of the heat pump 20 is determined so that the temperature of the drying air is as high as possible (step 304).

  Next, it is determined whether or not the specifications (temperature / flow rate) of the drying air can be satisfied only by the output of the heat pump 20 (step 305). When the air specification is satisfied, a condition in which no heat medium is supplied from the boiler 40 is set (step 306). When the air specification is not satisfied, the steam flow rate from the boiler 40 is determined using the equation (5) (step 307).

  Next, based on the determined steam flow rate, calculation relating to feed water heating (preheating in the boiler 40) by the heat pump 20 is performed (step 308). Similarly, in the case where the feed water heating by the heat pump 20 (preheating in the boiler 40) is “present”, the necessary steam flow rate from the boiler 40 is similarly calculated (step 309).

Next, the primary energy efficiency of the entire system S1 is calculated for both the case of “with water supply heating” and the case of “without water supply heating” (step 310). Primary energy efficiency = COP × power generation efficiency × W _HP / W _D + boiler efficiency × W _B / W _D.

  Further, the evaluation of the primary energy, economic efficiency, and environmental performance of the system S1 can be evaluated (step 311). For this evaluation, for example, a predetermined index relating to economic efficiency and environmental performance can be used.

  In step 311, it can be determined whether or not the energy saving optimization in the entire system S <b> 1 has been completed. If not completed, the output of the heat pump 20 and / or the feed water heating amount (temperature, preheating amount) can be changed (step 312). In this case, the primary energy efficiency is calculated in the same manner as described above for the predetermined load state of the heat pump 20 between the full load and the partial load. Calculation is performed for a plurality of load states of the heat pump 20, and as a result, optimum values can be obtained for the load state of the heat pump 20 and the feed water heating amount. That is, the control device 18 can optimize the load ratio of the heat pump 20 and the feed water heating amount (preheating amount) in the boiler 40.

  The above series of flows can be performed, for example, when the heat demand or the low temperature heat source conditions change. The system S1 can implement stable heat supply with high energy efficiency based on the optimum conditions.

  In the above flow, the operation of the heat pump 20 can be performed according to the low temperature heat source condition (warm exhaust heat condition) in accordance with the heat demand for drying. When the heat output of the heat pump 20 is insufficient, it can be supplemented with steam from the boiler 40.

  Moreover, in the said flow, the feed water heating (preheating) of the boiler 40 can be implemented using the heat pump 20, the feed water heating temperature can be adjusted to some extent, and it can be set so that the whole system S1 can save energy.

  In the primary energy evaluation of the system S1, the following values are considered as an example: COP (Coefficient of Performance): 3, power generation efficiency: 40%, boiler efficiency: 90%. In this case, basically, the primary energy efficiency of the heat pump 20 is 120%, and it is advantageous to increase the operating rate of the heat pump 20.

  However, in the heat pump 20, as shown in FIGS. 5 and 6, there is a case where the partial load efficiency is higher than the constant load efficiency. That is, there are cases where the overall efficiency is relatively high when the output ratio of the heat pump 20 is lowered. Specifically, when the temperature of the low-temperature heat source is high, that is, when the pressure ratio is small, the partial load efficiency may be relatively high. By controlling the entire system S1 including the partial load operation of the heat pump 20, the energy efficiency can be improved.

Here, primary energy efficiency is calculated for the following cases. COP: 3 (rated), power generation efficiency: 40%, W _D : 100 kW, boiler efficiency: 90%.

(1) Supply the total amount of heat only by the heat pump 20 For example, W _H : 100 kW, COP: 3 (rated).
Primary energy efficiency = COP × generating efficiency × _W HP / _{W D} + boiler efficiency × _W B / _{W D}
= 3 x 0.4 x 100/100 + 0.9 x 0/100
= 1.2

(2) the heat pump part load operation for _example, W D: _50kW, COP: a 3 (rating).
Primary energy efficiency = COP × generating efficiency × _W HP / _{W D} + boiler efficiency × _W B / _{W D}
= 5 x 0.4 x 50/100 + 0.9 x 50/100
= 1.45

  That is, in the heat pump 20 having a COP of 3 in the entire operation (100 kW) in the above example, when the COP in the partial load operation (50 kW) is 5, the primary energy efficiency of the heat pump 20 is 145%.

(3) Heat pump partial load operation + boiler feed water heating For example, it is assumed that boiler feed water heating is carried out from the state of (2) above and W _HP : 55 and W _B : 45 are obtained.
Primary energy efficiency = COP × generating efficiency × _W HP / _{W D} + boiler efficiency × _W B / _{W D}
= 5 x 0.4 x 55/100 + 0.9 x 45/100
= 1.505

  Thus, the efficiency of the entire system S1 may be improved by performing feed water heating (preheating) in the boiler 40.

  By considering the partial load operation region of the heat pump 20 and the feed water heating (preheating) in the boiler 40 using the heat pump 20, the degree of freedom of operation of the heat pump 20 is expanded, and the maximum efficiency of the system S1 can be obtained in a wide range. Is possible. That is, the system S1 has a wide degree of freedom of the heat pump 20, and can obtain a substantial maximum efficiency in a wide range.

  Although the heat output of the heat pump 20 is affected by the amount of the low-temperature heat source, the heat demand can be stably satisfied by the configuration of the system S1. By optimizing the output ratio between the heat pump 20 and the boiler 40, it is possible to contribute to the reduction of primary energy. That is, according to the present embodiment, even if the amount of heat and temperature supplied from the low-temperature heat source are unstable, it is possible to stably meet the heat demand. Moreover, optimization of the output ratio of the heat pump 20 and the boiler 40 is achieved, and as a result, it can contribute to reduction of primary energy.

  FIG. 7 is a schematic diagram showing a heat supply system S2 in another embodiment. In the following description, the same components as those in the above embodiment are denoted by the same reference numerals, and the description thereof is omitted or simplified.

  As shown in FIG. 2, the heat supply system S2 includes a first heating device (first device) 12 having a heat pump (heat pump circuit) 20 and a heating device other than the heat pump, like the system S1 in FIG. A two-heating device (second device) 14, a supply device 16, and a control device 18 are provided. The control device 18 comprehensively controls the entire system. The configuration of the heat supply system S2 can be variously changed according to design requirements.

  In the present embodiment, the second heating device 14 includes an electric heater 48 as a heating device other than the heat pump.

  In the present embodiment, the supply device 16 supplies the fluid (heated fluid) heated using the first heating device 12 and the second heating device 14 (electric heater 48) to the external device 95. The supply device 16 includes a first heating unit 62 and a second heating unit 64. The supply device 16 can further include a conduit through which the fluid to be heated flows, a fluid drive device such as a pump, a valve for fluid control, and the like.

  In the present embodiment, the fluid to be heated is air, and high temperature air (drying air) is supplied to the external device 95. In other embodiments, the fluid to be heated can be air other than drying or a fluid other than air. Examples of heated fluids other than air include compressed water, chemicals, and viscous liquids.

  The first heating unit 62 includes a conduit that is thermally connected to the heat radiating unit 23 of the heat pump 20 in the first heating device 12 and through which air flows. The heat exchanger 32 is configured including the first heating unit 62 and the heat radiating unit 23. In the first heating unit 62, the temperature of the air in the conduit rises due to the heat transferred from the heat radiating unit 23 of the heat pump 20.

  The second heating unit 64 includes a conduit that is thermally connected to the heat radiating unit 148 of the electric heater 48 in the second heating device 14 and through which air from the first heating unit 62 flows. In the present embodiment, the heat radiation part 148 and the conduit of the second heating part 64 are arranged in contact with or adjacent to each other. For example, the heat radiating unit 148 can be disposed on the outer peripheral surface or inside of the conduit of the second heating unit 64. In the second heating unit 64, the temperature of the air in the conduit further increases due to the heat transferred from the heat radiating unit 148 of the second heating device 14.

  In the present embodiment, the output temperature of the fluid to be heated (drying air) from the supply device 16 can be changed according to the heat demand. The output temperature can be, for example, 50, 60, 70, 80, 90, 100, 110, 120, 130, 140, 150, 160, 170, 180, 190, or 200 ° C. or higher.

  In the present embodiment, the system S2 has a second return path 72 for reusing the heated fluid (exhaust gas) from the external device 95 after heat output. The fluid after radiating heat from the external device 95 flows through the second return path 72. The fluid (air) from the second return path 72 flows through the heat radiating pipe 74. The heat radiating pipe 74 of the second return path 72 is thermally connected to a conduit 93 fluidly connected to the heat radiating pipe 91 of the external device 90 on the low temperature heat source side. The heat of the fluid (air) from the second return path 72 is absorbed by the medium (refrigerant etc.) flowing through the conduit 93. The medium flows through the heat radiating pipe 91, and the heat is absorbed by the heat absorbing portion 21 of the heat pump 20. By reusing the fluid, the operation cost can be reduced.

  In the present embodiment, the system S2 includes heat demand information (required temperature, required flow rate) in the external device 95, output information (temperature, etc.) of the electric heater 48, and low-temperature heat source information for the heat pump 20 (exhaust heat information in the external device 90). Etc.) as necessary. The control device 18 can comprehensively control the entire system S2 based on various information.

  In the present embodiment, the control device 18 can control the operation of the heat pump 20 in a load state between a full load including a partial load state and no load. According to the present embodiment, the energy efficiency of the entire system S2 can be improved by the control including the partial load operation of the heat pump 20 and the backup by the electric heater 48.

  In the present embodiment, air (fluid supplied to the external device 95) as a fluid to be heated heated using the heat pump 20 can be further heated using the electric heater 48. Therefore, a relatively high temperature fluid can be supplied to the external device 95, and it can flexibly respond to a relatively high level of heat demand.

  As mentioned above, although embodiment of this invention was described, this invention is not limited to said embodiment. The numerical value used in the above description is an example, and the present invention is not limited to this. Additions, omissions, substitutions, and other modifications can be made without departing from the spirit of the present invention. The present invention is not limited by the above description, but only by the appended claims.

  S1, S2: heat supply system, 20: heat pump, 12: first heating device (first device), 14: second heating device (second device), 16: supply device, 18: control device, 40: boiler, 42: combustion chamber, 48: electric heater, 62: first heating unit, 64: second heating unit, 63: mixing unit (mixer), 64: output unit, 70: first return path, 72: second return Route, 90, 95: External device, 142: Preheating part (feed water heating part), 144: Heating part.

Claims (4)

A supply device for supplying air to an external device;
A first device including a heat pump through which a second fluid flows, wherein the first device is capable of transferring heat of the second fluid to the air;
A second device for heating the air from the first device;
A controller for controlling the heat pump in a load state between a full load and a no load including a partial load state , and
The second device heats a third fluid, and heat of the third fluid can be transferred to the air from the first device;
The heat pump has a heat absorption part capable of absorbing heat from the third fluid discharged from the second device,
The heat absorbing part can further absorb heat from the air discharged from the external device,
The second device is a boiler having a combustion chamber for heating the air;
The control device controls a load ratio of the heat pump based on a flow rate of air required in the external device and a primary energy efficiency.
Heat supply system. The second apparatus includes a preheater heat of the second fluid flowing through the heat pump is transferred to the third fluid, and a heating unit for heating the third fluid from the preheating unit, in claim 1 The heat supply system described. The control device includes information on a temperature and a flow rate of a low-temperature heat source supplied from the outside to the heat pump, a flow rate of the air required in the external device, an outlet condition of the second device, and a primary energy efficiency. The heat supply system according to claim 1 or 2 , wherein a load ratio of the heat pump and a heating amount of the third fluid in the preheating unit are controlled based on the heat pump. Heating the third fluid wherein the second fluid heating the air is thereafter, heat supply system according to any one of claims 1 to 3.

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